Facing severe drought, California's state water board told hundreds of users of the Sacramento River, including farms and some small cities, that they must stop taking water from the river.
The notices are the first such mandatory restrictions of water rights in the state this year, though officials and experts predict that more tightening will be announced in the coming weeks.
The reason for the action is simple, says George Kostyrko, a spokesman for the state's water board: The Sacramento River watershed, which serves much of northern and central California, does not currently have enough surface water to provide for all registered water users.
That's why the board, in accordance with state law, began on Wednesday evening to issue notices to 2,648 holders of "junior water rights"—including many farmers and property owners and even some municipal water authorities—that they must stop using water from the river.
Larger cities like Sacramento are not currently affected by the restrictions because they control "senior water rights," according to the state's laws.
That situation could change, however. "Based on projections of the available water, we will continue to issue curtailment notices by priority," says Kostyrko. In other words, although the junior water rights holders are the first to lose their access, others might be affected if the drought worsens.
"It works both ways," Kostyrko notes. "We are also committed to lifting restrictions whenever possible, as quickly as possible, if there is more water available."
Peter Gleick, an expert on water issues at the Pacific Institute in Oakland, California, says the drought has "highlighted the mismatch between water supply and the water rights that have been allocated."
"I think this kind of curtailment has been a long time coming and in some ways is overdue," he says.
Kostyrko says the water board may be required to issue limits on water use in other watersheds around the state in the coming weeks.
That would make the current drought the most serious since 1976-1977, when numerous restrictions were in place. Curtailments were issued on a smaller scale in California in the late 1980s, and over the past 12 years in the Sacramento-San Joaquin Rivers Delta.
Mt. Shasta Ski Park struggled this year thanks to low snowpack in the Cascades and Sierra Nevada, which is the source of much of the state's water supply.
PHOTOGRAPH BY PETER ESSICK, NATIONAL GEOGRAPHIC
Who Is Affected?
Many different groups of people will see their water rights curtailed in the Sacramento Valley, says David Guy, president of the Northern California Water Association, which represents property owners and water agencies in the region. Farmers, duck hunting clubs, and small cities are among those affected.
"Most of the people who are going to get these notices aren't going to be surprised," says Guy.
Warnings were sent out to junior water holders in January that restrictions might be coming. And many of the people in the area recall the drought of the 1970s, or have family members who remember it.
"People get really creative in finding alternative supplies if they can," adds Guy. "It might be groundwater or transferring water from a neighbor to get by."
Still, Guy warns that many farmers are going to be forced to leave their fields fallow, if they haven't done so already in anticipation of the drought. "There is no question that these cutbacks are going to be really hard on the region," he says.
Exemptions are made in some cases—for protecting health and safety, for instance—and users will have the option of turning to alternative sources of water, including groundwater.
Those who might try to skirt the new curtailments, however, face the possibility of legal action once the water board begins monitoring in the coming weeks, says Guy.
Gleick adds that enforcement will be key to the program actually saving water.
Low water levels are also seen at Folsom Lake, a reservoir about 25 miles (40 kilometers) northeast of Sacramento.
PHOTOGRAPH BY PETER ESSICK, NATIONAL GEOGRAPHIC
Kostyrko says the possibility of further restrictions relates in part to a separate law that requires a minimum amount of flow in the Sacramento River system to allow endangered species of fish to survive and migrate.
Besides endangered fish, other animals that rely on the river include migratory birds.
"It's not just the economy of the region that is challenged," says Guy. "So is the environment." (See "The American Nile.")
The latest action follows California Governor Jerry Brown's declaration of a state of drought emergency in January, and his call for additional cuts in water use in late April. "The driest months are still to come in California and extreme drought conditions will get worse," Brown said.
The governor has called for all Californians to reduce water use by 20 percent. He has also asked for increased monitoring and has made it easier for users to make voluntary transfers of water, especially to farmers.
A number of local entities have passed measures (see "5 Dramatic Ways California is Tackling Drought") similar to those imposed by the state. For example, the city of Sacramento has been working to install water meters for those who lack them and has launched a program to compensate homeowners for converting grass lawns to water-free alternatives.
Guy says such measures have helped reduce demand, but "some people could probably be doing more."
Gleick agrees that voluntary measures are helpful, but he cautions that overall "there has not been a strong enough response to the drought." The long-term solution, he says, is to ensure that all senior water rights users are making withdrawals that are "reasonable and beneficial."
Those two words are written into the state's constitution when it comes to water rights, but they have rarely been enforced, says Gleick. As an example, many farmers use irrigation practices and equipment that result in wasted water.
He says a strong argument could be made that inefficient use of water should be considered unreasonable, "but it's going to be harder for the water board to enforce that."
Even if there is more rain in 2015 or the years following, "the state has reached peak water," says Gleick. "We don't have enough to satisfy everyone's demands."
Follow Brian Clark Howard on Twitter and Google+.